[PATCHv3 6/11] HWMON: Fixed point conversion gives linktime error

[Ashish Jangam]

Hi,

As requested approximation of battery temperature calculation with fixed point conversion is tried but it causes couple of link time errors, like undefined reference to __aeabi_i2d at sprintf(). Have a look at the function da9052_read_tbat(); we feel that this function should not be supported else there will be a prerequisite to the support the required floating point library. Enabling FPE_NWFPE support in the kernel gives the same link time errors.

Also have a look at the rest of the code and let us know your comments.

Signed-off-by: Ashish Jangam <ashish.jangam@xxxxxxxxxxxxxxx>
                   David Dajun Chen <dchen@xxxxxxxxxxx>
--
diff --git a/Documentation/hwmon/da9052 b/Documentation/hwmon/da9052
new file mode 100755
index 0000000..aab7318
--- /dev/null
+++ b/Documentation/hwmon/da9052
@@ -0,0 +1,61 @@
+Kernel driver da9052-hwmon
+==========================
+
+Supported chips:
+  * Dialog Semiconductors DA9052 PMICs
+    Prefix: 'da9052'
+    Datasheet: Kindly visit www.dialog-semiconductor.com and request for the
+               official datasheet.
+
+Authors: David Dajun Chen <dchen@xxxxxxxxxxx>
+
+Description
+-----------
+
+The DA9052 provides an Analogue to Digital Converter (ADC) with 10 bits
+resolution and track and hold circuitry combined with an analogue input
+multiplexer. The analogue input multiplexer will allow conversion of up to 10
+different inputs. The track and hold circuit ensures stable input voltages at
+the input of the ADC during the conversion.
+
+The ADC is used to measure the following inputs:
+Channel 0: VDDOUT - measurement of the system voltage
+Channel 1: ICH - internal battery charger current measurement
+Channel 2: TBAT - output from the battery NTC
+Channel 3: VBAT - measurement of the battery voltage
+Channel 4: ADC_IN4 - high impedance input (0 - 2.5V)
+Channel 5: ADC_IN5 - high impedance input (0 - 2.5V)
+Channel 6: ADC_IN6 - high impedance input (0 - 2.5V)
+Channel 7: XY - TSI interface to measure the X and Y voltage of the touch
+screen resistive potentiometers
+Channel 8: Internal Tjunc. - sense (internal temp. sensor)
+Channel 9: VBBAT - measurement of the backup battery voltage
+
+By using sysfs attributes we can measure the system voltage VDDOUT, the battery
+charging current ICH, battery temperature TBAT, battery junction temperature
+TJUNC, battery voltage VBAT and the back up battery voltage VBBAT.
+
+Voltage Monitoring
+------------------
+
+Voltages are sampled by a 10 bit ADC.  Voltages in millivolts are 1.465
+times the ADC value.
+
+Temperature Monitoring
+----------------------
+
+Temperatures are sampled by a 10 bit ADC.  Junction and battery temperatures
+are monitored by the ADC channels.
+
+The junction temperature is calculated:
+       Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8
+The junction temperature attribute is supported by the driver.
+
+The battery temperature is calculated:
+       Degree Celcius = 1 / (t1 + 1/298)- 273
+where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255))
+Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively.
+
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 3236a45..da5ff6d 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -303,6 +303,16 @@ config SENSORS_DS1621
          This driver can also be built as a module.  If so, the module
          will be called ds1621.

+config SENSORS_DA9052_ADC
+        tristate "Dialog DA9052 HWMON"
+        depends on PMIC_DA9052
+        help
+          Say y here to support the ADC found on
+          Dialog Semiconductor DA9052 PMIC.
+
+          This driver can also be built as module. If so, the module
+          will be called da9052-hwmon.
+
 config SENSORS_I5K_AMB
        tristate "FB-DIMM AMB temperature sensor on Intel 5000 series chipsets"
        depends on PCI && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f7c0c28..88b81ca 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_SENSORS_ASC7621) += asc7621.o
 obj-$(CONFIG_SENSORS_ATXP1)    += atxp1.o
 obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o
 obj-$(CONFIG_SENSORS_PKGTEMP)  += pkgtemp.o
+obj-$(CONFIG_SENSORS_DA9052_ADC)       += da9052-hwmon.o
 obj-$(CONFIG_SENSORS_DME1737)  += dme1737.o
 obj-$(CONFIG_SENSORS_DS620)    += ds620.o
 obj-$(CONFIG_SENSORS_DS1621)   += ds1621.o
diff --git a/drivers/hwmon/da9052-hwmon.c b/drivers/hwmon/da9052-hwmon.c
new file mode 100755
index 0000000..6ec5b0b
--- /dev/null
+++ b/drivers/hwmon/da9052-hwmon.c
@@ -0,0 +1,377 @@
+/*
+ * HWMON Driver for Dialog DA9052
+ *
+ * Copyright(c) 2011 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@xxxxxxxxxxx>
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/da9052/da9052.h>
+#include <linux/mfd/da9052/reg.h>
+
+struct da9052_hwmon {
+       struct da9052   *da9052;
+       struct device   *class_device;
+       struct mutex    hwmon_lock;
+};
+static const char * const input_names[] = {
+       [DA9052_ADC_VDDOUT]     =       "VDDOUT",
+       [DA9052_ADC_ICH]                =       "CHARGING CURRENT",
+       [DA9052_ADC_TBAT]               =       "BATTERY TEMP",
+       [DA9052_ADC_VBAT]               =       "BATTERY VOLTAGE",
+       [DA9052_ADC_IN4]                =       "ADC IN4",
+       [DA9052_ADC_IN5]                =       "ADC IN5",
+       [DA9052_ADC_IN6]                =       "ADC IN6",
+       [DA9052_ADC_TJUNC]      =       "BATTERY JUNCTION TEMP",
+       [DA9052_ADC_VBBAT]      =       "BACK-UP BATTERY VOLTAGE",
+};
+
+static int da9052_enable_vddout_channel(struct da9052 *da9052)
+{
+       int ret;
+
+       ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG);
+       if (ret < 0)
+               return ret;
+
+       ret |= DA9052_ADCCONT_AUTOVDDEN;
+       return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret);
+}
+
+static int da9052_disable_vddout_channel(struct da9052 *da9052)
+{
+       int ret;
+
+       ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG);
+       if (ret < 0)
+               return ret;
+
+       ret &= ~DA9052_ADCCONT_AUTOVDDEN;
+       return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret);
+
+}
+
+static ssize_t da9052_read_vddout(struct device *dev,
+       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int ret
+       int vdd = -1;
+
+       mutex_lock(&hwmon->hwmon_lock);
+
+       ret = da9052_enable_vddout_channel(hwmon->da9052);
+       if (ret < 0)
+               goto hwmon_err;
+
+       ret = da9052_reg_read(hwmon->da9052, DA9052_VDD_RES_REG);
+       if (ret < 0)
+               pr_err("Failed to read VDD_RES_REG\n");
+       else
+               vdd = ret;
+
+       ret = da9052_disable_vddout_channel(hwmon->da9052);
+       if (ret < 0)
+               goto hwmon_err;
+
+       if (vdd) {
+               mutex_unlock(&hwmon->hwmon_lock);
+               return sprintf(buf, "%d\n", vdd);
+       }
+hwmon_err:
+       mutex_unlock(&hwmon->hwmon_lock);
+       return ret;
+}
+
+static ssize_t da9052_read_ich(struct device *dev,
+       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int ret;
+
+       ret = da9052_reg_read(hwmon->da9052, DA9052_ICHG_AV_REG);
+       if (ret < 0)
+               return ret;
+
+       /* Equivalent to 3.9mA/bit in register ICHG_AV */
+       ret = DIV_ROUND_CLOSEST(ret * 39, 10);
+       return sprintf(buf, "%d\n", ret);
+}
+
+#define BCONST         3380
+#define LOGN2          0.693147181
+#define TBAT_DIV               0.003355705
+/* ln(x) = log2(x) * ln(2) = log2(x) * 0.693147181
+   log2(float) gets convert to fixed point as = log2(nr) - log2(dr) */
+#define CAL_LOG2(nr)   ((ilog2(nr) - ilog2(100)) * LOGN2)
+/*
+       The battery temperature is calculated as:
+       Degree Celcius = 1 / (t1 + 1/298)- 273
+       where t1 = (1/B)* ln((ADCval * 2.5)/(R25*ITBAT*255))
+       And R25 = 10e3, B = 3380 and ITBAT = 50e-6
+*/
+static int cal_temperature(int adc_val)
+{
+       int nr;
+       int temperature_k;
+
+       /* Formula 2.5/(R25*ITBAT*255) gets reduced to 2, for fixed point
+          conversion */
+       nr = adc_val * 2;
+
+       /* Temperature in Kelvin =
+          1 / ((1 / bconst) * CAL_LOG(nr) + 0.003355705) */
+       temperature_k = 10000 / (3 * CAL_LOG2(nr) + 34);
+
+       /* Battery temperature in degree celcius */
+       return temperature_k - 273;
+}
+
+static ssize_t da9052_read_tbat(struct device *dev,
+                       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int ret;
+       int tbat;
+
+       ret = da9052_reg_read(hwmon->da9052, DA9052_TBAT_RES_REG);
+       if (ret < 0)
+               return ret;
+
+       tbat = cal_temperature(ret);
+
+       return sprintf(buf, "%d\n", (tbat*1000));
+}
+
+static ssize_t da9052_read_vbat(struct device *dev,
+       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int ret;
+
+       ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBAT);
+       if (ret < 0)
+               return ret;
+
+       return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t da9052_read_misc_channel(struct device *dev,
+       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int channel = to_sensor_dev_attr(devattr)->index;
+       int ret;
+
+       ret = da9052_adc_manual_read(hwmon->da9052, channel);
+       if (ret < 0)
+               return ret;
+
+       return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t da9052_read_tjunc(struct device *dev,
+       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int temp;
+       int ret;
+
+       ret = da9052_reg_read(hwmon->da9052, DA9052_TJUNC_RES_REG);
+       if (ret < 0)
+               return ret;
+
+       temp = ret;
+
+       ret = da9052_reg_read(hwmon->da9052, DA9052_T_OFFSET_REG);
+       if (ret < 0)
+               return ret;
+
+       /* Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 */
+       ret = 1708 * (temp - ret) - 108800;
+       return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t da9052_read_vbbat(struct device *dev,
+       struct device_attribute *devattr, char *buf)
+{
+       struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+       int ret;
+
+       ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBBAT);
+       if (ret < 0)
+               return ret;
+
+       return sprintf(buf, "%d\n", ret);
+
+}
+
+static ssize_t da9052_hwmon_show_name(struct device *dev,
+               struct device_attribute *devattr, char *buf)
+{
+       return sprintf(buf, "da9052-hwmon\n");
+}
+
+static ssize_t show_label(struct device *dev,
+                         struct device_attribute *devattr, char *buf)
+{
+       return sprintf(buf, "%s\n",
+                       input_names[to_sensor_dev_attr(devattr)->index]);
+}
+
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, da9052_read_vddout, NULL,
+                               DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, da9052_read_vbat, NULL,
+                               DA9052_ADC_VBAT);
+static SENSOR_DEVICE_ATTR(in3_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_VBAT);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, da9052_read_misc_channel, NULL,
+                               DA9052_ADC_IN4);
+static SENSOR_DEVICE_ATTR(in4_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_IN4);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, da9052_read_misc_channel, NULL,
+                               DA9052_ADC_IN5);
+static SENSOR_DEVICE_ATTR(in5_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_IN5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, da9052_read_misc_channel, NULL,
+                               DA9052_ADC_IN6);
+static SENSOR_DEVICE_ATTR(in6_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_IN6);
+static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, da9052_read_vbbat, NULL,
+                               DA9052_ADC_VBBAT);
+static SENSOR_DEVICE_ATTR(in9_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_VBBAT);
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, da9052_read_ich, NULL,
+                               DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(curr1_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_ICH);
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, da9052_read_tbat, NULL,
+                               DA9052_ADC_TBAT);
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_TBAT);
+
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, da9052_read_tjunc, NULL,
+                               DA9052_ADC_TJUNC);
+static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, show_label, NULL,
+                               DA9052_ADC_TJUNC);
+
+static DEVICE_ATTR(name, S_IRUGO, da9052_hwmon_show_name, NULL);
+
+static struct attribute *da9052_attr[] = {
+       &dev_attr_name.attr,
+
+       &sensor_dev_attr_in0_input.dev_attr.attr,
+       &sensor_dev_attr_in0_label.dev_attr.attr,
+       &sensor_dev_attr_curr1_input.dev_attr.attr,
+       &sensor_dev_attr_curr1_label.dev_attr.attr,
+       &sensor_dev_attr_temp1_input.dev_attr.attr,
+       &sensor_dev_attr_temp1_label.dev_attr.attr,
+       &sensor_dev_attr_in3_input.dev_attr.attr,
+       &sensor_dev_attr_in3_label.dev_attr.attr,
+       &sensor_dev_attr_in4_input.dev_attr.attr,
+       &sensor_dev_attr_in4_label.dev_attr.attr,
+       &sensor_dev_attr_in5_input.dev_attr.attr,
+       &sensor_dev_attr_in5_label.dev_attr.attr,
+       &sensor_dev_attr_in6_input.dev_attr.attr,
+       &sensor_dev_attr_in6_label.dev_attr.attr,
+       &sensor_dev_attr_temp1_input.dev_attr.attr,
+       &sensor_dev_attr_temp1_label.dev_attr.attr,
+       &sensor_dev_attr_temp2_input.dev_attr.attr,
+       &sensor_dev_attr_temp2_label.dev_attr.attr,
+       &sensor_dev_attr_in9_input.dev_attr.attr,
+       &sensor_dev_attr_in9_label.dev_attr.attr,
+       NULL
+};
+
+static const struct attribute_group da9052_attr_group = {.attrs = da9052_attr};
+
+static int __init da9052_hwmon_probe(struct platform_device *pdev)
+{
+       struct da9052_hwmon *hwmon;
+       int ret;
+
+       hwmon = kzalloc(sizeof(struct da9052_hwmon), GFP_KERNEL);
+       if (!hwmon)
+               return -ENOMEM;
+
+       mutex_init(&hwmon->hwmon_lock);
+       hwmon->da9052 = dev_get_drvdata(pdev->dev.parent);
+
+       platform_set_drvdata(pdev, hwmon);
+
+       ret = sysfs_create_group(&pdev->dev.kobj, &da9052_attr_group);
+       if (ret)
+               goto err_mem;
+
+       hwmon->class_device = hwmon_device_register(&pdev->dev);
+       if (IS_ERR(hwmon->class_device)) {
+               ret = PTR_ERR(hwmon->class_device);
+               sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
+               goto err_mem;
+       }
+
+       return 0;
+
+err_mem:
+       kfree(hwmon);
+       return ret;
+}
+
+static int __devexit da9052_hwmon_remove(struct platform_device *pdev)
+{
+       struct da9052_hwmon *hwmon = platform_get_drvdata(pdev);
+
+       hwmon_device_unregister(hwmon->class_device);
+       sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
+       mutex_destroy(&hwmon->hwmon_lock);
+       kfree(hwmon);
+
+       return 0;
+}
+
+static struct platform_driver da9052_hwmon_driver = {
+       .driver = {
+               .name   = "da9052-hwmon",
+               .owner  = THIS_MODULE,
+       },
+       .probe          = da9052_hwmon_probe,
+       .remove         = __devexit_p(da9052_hwmon_remove),
+
+};
+
+static int __init da9052_hwmon_init(void)
+{
+
+       return platform_driver_register(&da9052_hwmon_driver);
+}
+module_init(da9052_hwmon_init);
+
+static void __exit da9052_hwmon_exit(void)
+{
+       platform_driver_unregister(&da9052_hwmon_driver);
+}
+module_exit(da9052_hwmon_exit);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("DA9052 HWMON driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9052-hwmon");


Regards,
Ashish


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